so I decided to test the corsair link on the RM750i & downloaded latest version v4.9.7.35 which installed on win7 64

turns out the app works well - too well :/

after tinkering a bit with the fan control & setting it to custom (which btw is similar to the seasonics hybrid mode: fan is minimum 40% then increases with load) I decided I didn't need the fan & opted to preserve fan life by returning to default mode (0 rpm on low loads)

the snag is I didn't reset to default in corsair link: I outright uninstalled the app while fan settings were still set at custom (Aida shows all the info even without CL installed as long as the usb cable's plugged into the mobo anyway)

...and to my surprise the fan remained at 40% on idle even after I uninstalled the app

I of course uninstalled both the CL app and the Corsair drivers compoents (in program manager), I even removed all corsair-related entries from registry & all corsair-related files & folders (as far as I can tell) and still the fan settings are where I left them before uninstalling CL

weirder still those settings seem to apply even outside windows: when PC starts, in BIOS etc.: the fan starts spinning (at 40% I presume, can't even hear it admittedly it's silent AF) and doesn't stop until shutdown

so basically I was wondering if the link settings survive uninstall of the link app because they're in fact stored in a CMOS of sorts

I mean when you think about it it's a bit like overclocking apps like MSI afterburner: when overclocking a graphics card it's necessary to do it at every boot else the card settings revert back to default after PC is powered off

but in the case of the PSU it's not the same apparently is that correct? so the settings are stored in the PSU?

I reckon only a Corsair engineer could answer this so the question's addressed at them

Many of the "i" devices that have software control over the fan or device in some way also have the ability to save a simple control parameter to the device itself, which then governs behavior in the absence of the controlling software. This is most easily seen on the coolers, but I am not surprised the i-enabled PSUs work the same way.

Now you could have reinstalled Link and set a different fan profile in less time than it takes to write the post, but that may not matter anyway. Typically, once you overwrite the original fan profile on a device, there is no magic reset to put it back exactly as it was. You can certainly change it and the new one will apply, but you would need to know the prior curves control points. You would need a very methodical 750i owner who tracks this or the better path might be contacting Corsair officially through the Ticket Support System in the menu above. My guess is the PSU has silent mode, an initial fan start up point at temperature XX, then a maximum fan speed at 50-60C somewhere. I don't have this model, but several of my other branded PSUs have their factory control curve right on the side of the box. It would be easy to approximate it. It also might not matter so much. You know you need a good bit of fan speed at 50C. What happens underneath that is up to you. I prefer silent at sub 30C to keep it off on the desktop and then even the smallest bit of fan speed works better than passive when loaded.

Afterburner and Precision XOC/X1 or similar programs are not going to be able to write to a cross-brand device by design. It is software overclocking and it is meant to be temporary. This is a Corsair program talking to a Corsair device. It was meant to used with the software, but obviously it still functions without. The act of installing the software, making a change, then uninstalling the software is a relinquishment of control, whatever your reasons for doing so. You have to live with it if you choose that path.

I am not going to get into the single rail vs multi "danger" discussion since it is both hypothetical and not my area of expertise. If we were having an argument, I would not concede the point of "inviting danger" by switching to single rail. I also suspect there is fail safe trigger point for max fan speed, regardless of your settings, to prevent such an occurrence.

There are probably only one or two people who can answer your hypotheticals. I do not know if they will respond or not and I would suggest requesting the information from Corsair through the ticket system. Not sure if that will be what you want either, but no reason not to work both ends.

btw apparently reinstalling Corsair Link resets the PSU fan settings to default (no need to even change settings & manually revert to default) so that's one way to reset (still needs software but at least simpler than expected)

anyway now that this answers the question (the PSU does store settings internally) I'm with another conundrum since my PC case has the PSU on top - where heat rises - I dunno if I should keep 0 fan setting or instead (re)set it to custom for a constant minimum speed regardless of load

I guess the real question is, how durable is a true FDB (fluid dynamic) fan compared to ball-bearing fans? (the latter being the most durable)?

I answered your other question in the cooling forum, but did not make the link to this issue at the time. I answered more in the context of case fans. While bearing lifespan does not change from case fan to PSU, how you analyze it might.

As PSU warranties get into the 5-10 year range, then wearing out the fan in the box may actually become a warranty claim point. If I really intended to use the same PSU for the next 10 years, I know what kind of bearing I would want. On the other hand, swapping in a different fan is a fairly simple and likely the only thing most users should attempt when working with their power supply. Of course, opening the PSU ends your warranty solving point 1 from the manufacturer's end.

More narrowly, if you intent is to make the PSU last as long as possible without ever having to do anything, let the program turn the fan on and off with the FDB or ball bearing fan. Over a multu-year period, less hours in use is less hours in use. However, I don't think that should be the basis of your decision. Presumably this is for a server system or something else that is going to be on all the time. The better question is what's best for the system. Continuous cooling (even when the fan speed is low) will always result in lower average temperature over the long run compared to a stop/start pattern. I tell people this all the time with CPU coolers. However, the PSU is a bit different. If you have a normal environment and the machine is spending a lot of time in a lower power state, I don't see any need to keep the fan running. It is likely audible (may or may not matter), but it certainly isn't necessary until the temperature begins to climb. If this machine does not ever see a high load, it may never run and the PSU is quite happy at 30C. Whatever your uses are, load intensity, frequency, and temperature should be the basis for the decision and not whether the FDB fan will wear out in 6 or 7 years.

k so as I said in the other thread, zero-fan mode is better for my Corsair PSU not just because of the FDB fan but also because the PSU's at the bottom of the case (and I don't want it sucking up who knows what from beneath & getting clogged by dust especially since that filter ain't easy to remove so I'd have to flip the case...man who thef invented bottom-PSU configs when top-PSU cases were so much more practical ffs)

so when I reinstalled CL & it set the settings back to default 0fan mode, I then uninstalled it again - the PSU's default mode does a good enough job of handling its fan on its own right?

btw is the RMi's fan control load-based or thermal-based? or (ideally) both?

like does the fan automatically turn on at a preset minimum load and/or a preset minimum temperature?

personally I want it off as much as possible but I won't risk setting a "zero fan regardless of load" setting (I reckon only those new titanium-rated PSU's are safe with a total-fanless mode)

That's a good question regarding watts in use % or PSU temperature as the trigger. The literature suggests it is a watts produced control, but I don't know if that is really true or not. Since the standard assessment is watts@XX temperature, I somewhat expect all of them to really to kick the fan on based on temp. All of my PSUs do kick out of zero mode at XX temp, but then none of them are a Corsair 750 RMi. Perhaps someone else knows for sure.

since wattage can be measured more accurately than temps (thermal sensors can go wrong more easily no?) wattage would be a logical trigger

but then what happens if temps go up despite low load? eg. a small & poorly ventilated case
in which case it should also be temp-triggered

I've read instance of people using a hairdryer pointed at their RM (or RMx or RMi? cant remember) at highest setting where the inside of dryer glows red hot & it's impossible to keep their hand in front lest it burn yet even that wasnt enough to trigger the fan
so does that mean thermal sensor was faulty (doubtful else that's a serious quality flaw) or just that those PSU's are so heat-tolerant that thermal trigger's even higher...or does it mean it's only triggered on load?

You might consider posting the watts vs temp part of the question in the Power Supplies forum. I can think of a few people who might know, but they typically don't stray outside that particular area. With Link now replaced, this sub-forum doesn't get a lot of traffic.